April 1, 2015

• Action Points
  Note that this cohort study of rheumatoid arthritis patients demonstrated that coronary artery calcium scores were, surprisingly, lower among those who took more than 1,000 mg per day of calcium supplements.
• Be aware that this was not a randomized trial — the effects seen could be accounted for by a “healthy patient” effect whereby those who take supplements engage in other healthful activities that were not directly measured.

High coronary artery calcification (CAC) scores are significantly less frequent among patients with rheumatoid arthritis (RA) who take calcium supplements in large doses than they are among patients who take lesser amounts of daily calcium both at baseline and 3 years later, a new study shows.

Among a cohort of 145 patients with RA, baseline CAC scores >100 units — validated as a strong predictor of future cardiovascular (CV) clinical events — were 70% less frequent among subjects who ingested ≥1,000 mg/day supplemental calcium than in those who consumed <1,000 mg/day after adjusting for relevant confounders (Odds Ratio [OR] of 0.30 (95% CI 0.09-0.93).

Similarly, at a median of 39 months post-baseline measurements, CAC scores >100 units were 61% less frequent in the higher dose supplemental calcium group compared with the lower dose group although this was no longer statistically significant when adjusted for confounders at an OR of 0.39 (95% CI 0.14-1.12).

“To our knowledge, this is the first study to explore the association of oral calcium supplementation with coronary artery atherosclerosis in RA patients,” Laura Geraldino-Pardilla MD, Columbia University, College of Physicians and Surgeons, in New York City, and colleagues write in Arthritis and Rheumatology.

“And contrary to our hypothesis, our study suggests that calcium supplementation at doses greater or equal to 1,000 mg/day was not associated with a higher risk of coronary artery calcium, a measure of coronary atherosclerosis.”

Study participants were enrollees in the Evaluation of Subclinical Cardiovascular Disease and Predictors of Events in Rheumatoid Arthritis (ESCAPE-RA) study, a prospective cohort study that investigated subclinical CVD in RA.

Participants were between 45 and 84 years of age and had been diagnosed with RA for 6 months or longer.

A total of 145 patients had complete longitudinal data for calcium supplementation at baseline and at visit two at a median of 20 months from baseline and had two cardiac CT scans, one at baseline and another at visit three. Visit three was a median of 39 months from baseline.

The CAC score, a measure of coronary atherosclerosis, was assessed by cardiac multidetector row computed tomography at baseline and at visit three.

Calcium supplement data were derived from the medication list ascertained from prescription and nonprescription bottles brought by patients to the first and second study visits.

The primary outcome was the CAC score at both baseline and at the third visit.

“Overall, 71 (49%) patients were on calcium supplementation,” investigators observe.

Some 29% of patients were taking at least 1,000 mg of calcium supplementation a day while the remainder were taking less than 1,000 mg a day.

A CAC score >100 units was documented in 30% of patients at baseline and 34% of patients at the third visit.

In adjusted analysis, 16% of women had a CAC score of >100 units at baseline compared with 45% of men (P=0.0003).

Similarly, at study visit three, 25% of women had a CAC score >100 units compared with 47% of men also in the adjusted model (P=0.004).

Noteworthy as well, “98% of those with a CAC >100 units at baseline had persistently elevated CAC >100 units at visit three,” the authors write.

Limitations of the study include a lack of information on how long patients were taking calcium supplements prior to baseline: hence the potential benefit of high doses of calcium supplements beyond 39 months is not clear.

Investigators also did not measure dietary calcium or serum calcium levels which could have affected CAC scores.

The ESCAPE cohort was also predominantly Caucasian and results may not be generalizable to other racial or ethnic groups.

“The use of calcium supplements has been reported to increase overall cardiovascular-related deaths by approximately 20%,” the authors state.

“And this raises a relevant concern for RA patients in whom calcium supplements are routinely given for prevention of osteoporosis,” they add.

“[Since] our study suggests that calcium supplementation at doses greater or equal to 1,000 mg/day was not associated with a higher risk of coronary artery calcium … the pathophysiology and contributing factors to coronary artery atherosclerosis and cardiovascular disease in RA remain poorly understood.”

From the American Heart Association:

• 2013 ACC/AHA Guideline on the Assessment of Cardiovascular Risk
• Coronary CT Angiography
• ACCF/AHA 2007 Clinical Expert Consensus Document: Coronary Artery Calcium Scoring By Computed Tomography in Global Cardiovascular Risk Assessment

• Reviewed by F. Perry Wilson, MD, MSCEAssistant Professor, Section of Nephrology, Yale School of Medicine and Dorothy Caputo, MA, BSN, RN, Nurse Planner

LAST UPDATED 04.02.2015